I do.
I don't know if he's trying to pretend it's his own work or not but I know I have personally told him that he should put other people's words in quotation marks or a quote box to make it clear what he is writing and what he is copying. He makes it extremely confusing because he adds his own words and thoughts in ways that make it hard to figure out where his quoted material ends and his begins.
When you're engaged in a debate with someone else it is absolutely unacceptable to use other people's work in a way that makes it seem like it is your own.